Effect of temperature and water availability during late maturation of the soybean seed on germ and cotyledon isoflavone content and composition

BACKGROUND: Isoflavone content in soybean seeds is strongly influenced by both environment and genotype. However, little is known about the effect of environment and genotype on isoflavones in germ versus cotyledons. To determine the effect of temperature and soil moisture status during soybean seed development on seed isoflavone concentration and composition, a set of two French and three US cultivars of similar maturity were grown in the greenhouse. At the R6 growth stage, plants were subjected to one of three night/day temperature regimes (13/23°, 18/28° or 23/33 °C) in either optimal or sub‐optimal soil water conditions. RESULTS: In cotyledons, a three‐ to six‐fold variation in total isoflavone content was observed between the high and low temperature treatments, whereas the germ contents had less than a two‐fold variation. Soil water supply had less effect than temperature on the isoflavone contents and compositions. In both seed parts, the isoflavone concentrations were highly dependent on the cultivar. CONCLUSION: These results show that isoflavone content and composition in cotyledon and germ are unrelated and it should be possible to independently manipulate these seed traits through plant breeding and crop management systems. Copyright © 2007 Society of Chemical Industry     

Influence of packaging atmosphere on the formation of cholesterol oxides in γ-irradiated egg powder

In a previous work the effect of ionising radiation on formation of cholesterol oxidation products (COPs) under aerobic conditions was studied. In the present work the influence of aerobic and anoxic conditions have been comparatively investigated to study the chemical changes of cholesterol in γ-irradiated egg powder. The irradiation treatment was carried out with powdered egg packed under air and also under vacuum in polyethylene (PE) bags and in laminated, oxygen impermeable three-layer (polyester-aluminium-polyethylene) foil to dosage levels 2 and 4 kGy at room temperature. The cholesterol oxidation is demonstrated by thin-layer chromatograms. In the egg powder wrapped in PE bags the predominant cholesterol derivatives?7-hydroxycholesterol isomers (α and β)—accumulated in significant amounts (increasing with dose) while vacuum-packaging in laminated foil considerably suppressed the quantity of these products and prevented the formation of cholesterol 5α, 6α-epoxide as well as 7-ketocholesterol. Little or no change was observed in non-irradiated (control) vacuum-packed egg powder stored at approximately 22°C for up to 5 months. Peroxide values showed changes parallel to the formation of COPs.     

The impact of choline availability on muscle lipid metabolism

Consumption of choline-rich foods is essential to ensure membrane integrity, neurotransmission and genomic methylation pathways. Insufficient dietary choline supply can cause choline deficiency (CD) which manifests in the development of non-alcoholic fatty liver disease. There is very limited information regarding the effect of CD on non-hepatic tissues such as muscle. In this study, we induced CD in muscle cells and investigated the effect on choline transport, phosphatidylcholine (PC), fatty acid and triacylglycerol (TAG, fat) metabolism. Choline transport was stable across the plasma membrane of CD cells but significantly impaired in mitochondria. The main choline-transporter SLC44A1 was down-regulated by CD at the mRNA level, and SLC44A1 protein was reduced in total cell lysates and isolated mitochondria. CD significantly reduced PC synthesis but PC degradation was unaffected. PC from CD muscle was modified and contained more monounsaturated fatty acids at the expense of saturated fatty acids. Surprisingly, CD muscle cells also accumulated TAG in the form of large lipid droplets. Those droplets were formed from endogenous fatty acids and by slower TAG metabolism. This study established for the first time that choline availability affects muscle membrane lipid composition and intracellular lipid metabolism, and underlines the significance of choline-rich foods for proper muscle function.     

Production of enzymatic hydrolysates with antioxidant and angiotensin-I converting enzyme inhibitory activity from pumpkin oil cake protein isolate

Protein isolate from pumpkin oil cake (PuOC PI) was hydrolysed by alcalase, flavourzyme and by sequential use of these enzymes, respectively, and the antioxidant properties and angiotensin-I converting enzyme (ACE) inhibitory activities of hydrolysates were evaluated. Under the same reaction conditions, alcalase hydrolysates showed a higher degree of hydrolysis (DH) than did flavourzyme hydrolysates. The highest DH’s by individual enzymes were 53.23 ± 0.7% and 37.17 ± 1.05%, respectively, both at 60 min. The increase of radical scavenging activity (RSA) in hydrolysates was positively correlated with the increase of DH, for both enzymes, though hydrolysates with flavourzyme showed two- or three-fold lower RSA than with alcalase. The highest bioactive potential was determined in the alcalase hydrolysate at 60 min, with RSA being 7.59 ± 0.081 mM TEAC/mg and ACE-inhibitory activity 71.05 ± 7.5% (IC₅₀ = 0.422 mg/ml). When this hydrolysate was further hydrolysed by flavourzyme, DH increased up to 69.29 ± 0.9%, but lower RSA (4.82 ± 0.21 mM TEAC/mg) and ACE-inhibitory activity (55.81 ± 6.196%) were determined in the final hydrolysate. This study suggested that the PuOC proteins could be converted into protein hydrolysates with antioxidant and ACE-inhibitory activities by enzymatic hydrolysis. Alcalase was shown as promising enzyme in further development of bioprocesses for the production of new bioactive food ingredients.     

Polyphenol oxidase activity,phenolic acid composition and browning in cashew apple (Anacardium occidentale, L.) after processing

This study describes the extraction and characterisation of cashew apple polyphenol oxidase (PPO) and the effect of wounding on cashew apple phenolic acid composition, PPO activity and fruit browning. Purification factor was 59 at 95% (NH₄)₂SO₄ saturation. For PPO activity, the optimal substrate was catechol and the optimum pH was 6.5. PPO K_m and V_max values were 18.8 mM and 13.6 U min⁻¹ ml⁻¹, respectively. Ascorbic acid, citric acid, sodium sulphite and sodium metabisulphite decreased PPO activity, while sodium chloride increased PPO activity. Wounding at 2 °C and 27 °C for 24 h increased PPO activity but storage at 40 °C reduced PPO activity. Gallic acid, protocatechuic acid and cinnamic acid (free and conjugate) were identified in cashew apple juice. Cutting and subsequent storage at 40 °C hydrolysed cinnamic acid. 5-Hydroxymethylfurfural content in cashew apple juice increased after injury and storage at higher temperatures, indicating non-enzymatic browning.     

Influence of the composition of natural organic matter on Pb bioavailability to microalgae

The current work examines the effects of model allochtonous (humic substances) and autochtonous (microbial polysaccharides) natural organic matter (NOM) on Pb speciation and bioaccumulation. The results demonstrated that polysaccharides, in particular alginic acid, had complexing properties and effects on Pb bioaccumulation by the green alga Chlorella kesslerii that were similar to equivalent complexing capacity of humic substances. Pb uptake decreased in the presence of humic, alginic, and polygalacturonic acids with respect to noncomplexed Pb, but accumulated Pb was higher than predicted from measured Pb2+ concentrations or from previous results obtained in the presence of simple synthetic ligands. An improved fit between experimental observations and Pb speciation was obtained by taking into account the formation of a ternary complex at the algal surface. The contribution of the ternary complexes to Pb bioaccumulation was dependent on the relative binding constants of the Pb to the NOM and to the binding sites on the biological surface. In the presence of the humic acid, a decreased surface charge and increased membrane permeability were considered to be of secondary importance to explain the observation of increased Pb uptake with respect to that predicted on the basis of [Pb2+]. The environmental implications of the results are discussed with respect to the development of site-specific water quality criteria.     

Application of bacteriocinogenic Enterococcus mundtii CRL35 and Enterococcus faecium ST88Ch in the control of Listeria monocytogenes in fresh Minas cheese

Several strains of Enterococcus spp. are capable of producing bacteriocins with antimicrobial activity against important bacterial pathogens in dairy products. In this study, the bacteriocins produced by two Enterococcus strains (Enterococcus mundtii CRL35 and Enterococcus faecium ST88Ch), isolated from cheeses, were characterized and tested for their capability to control growth of Listeria monocytogenes 426 in experimentally contaminated fresh Minas cheese during refrigerated storage. Both strains were active against a variety of pathogenic and non-pathogenic microorganisms and bacteriocin absorption to various L. monocytogenes, Enterococcus faecalis ATCC 19443 and Lactobacillus sakei ATCC 15521 varied according to the strain and the testing conditions (pH, temperature, presence of salts and surfactants). Growth of L. monocytogenes 426 was inhibited in cheeses containing E. mundtii CRL35 up to 12 days at 8 °C, evidencing a bacteriostatic effect. E. faecium ST88Ch was less effective, as the bacteriostatic affect occurred only after 6 days at 8 °C. In cheeses containing nisin (12.5 mg/kg), less than one log reduction was observed. This research underlines the potential application of E. mundtii CRL35 in the control of L. monocytogenes in Minas cheese.     

Modelling the stability of lycopene-rich by-products of tomato processing

Tomato by-products were produced by puree manufacturing from heat-stabilised fruits and raw fruits to simulate both conventional and innovative processing technologies. By-products were freeze-dried, ground and stored in five relative humidity environments in the range 11–75%, for 4 months at 30 °C. The aims were: (a) to investigate the effect of heating applied during tomato processing on by-product hygroscopicity and stability, (b) to find out the optimal water activity (a_w) range for by-product stability. Hygroscopicity was studied by applying the Guggenheim–Anderson–de Boer (GAB) model. By-product stability was studied by evaluating the kinetics of lycopene, β-carotene, rutin and chlorogenic acid degradation and the changes in Hunter’s colourimetric parameters during storage.     

Total phenolic and carotenoid contents in acerola genotypes harvested at three ripening stages

Acerola fruits (Malpighia emarginata D.C.) were harvested from 12 different genotypes cultivated at the Active Germplasm Bank in Federal Rural University of Pernambuco, in the northeast region of Brazil. The effects of maturity stages and weather conditions on total phenolics and carotenoids content were analysed. Mature fruits harvested in the dry season showed the highest and the lowest levels of total phenolics and carotenoids, respectively. During the maturation process, phenolics degradation and carotenoids biosyntheses were observed. Among the acerola genotypes, fruits from genotype number 05 stood out, presenting the highest phenolic and carotenoid contents.     

Investigation of Chemical Constituents of Eranthis longistipitata (Ranunculaceae): Coumarins and Furochromones

Aqueous-ethanol extracts (70%) from the leaves of Eranthis longistipitata Regel. (Ranunculaceae Juss.)—collected from natural populations of Kyrgyzstan—were studied by liquid chromatography with high-resolution mass spectrometry (LC-HRMS). There was no variation of the metabolic profiles among plants that were collected from different populations. More than 160 compounds were found in the leaves, of which 72 were identified to the class level and 58 to the individual-compound level. The class of flavonoids proved to be the most widely represented (19 compounds), including six aglycones [quercetin, kaempferol, aromadendrin, 6-methoxytaxifolin, phloretin, and (+)-catechin] and mono- and diglycosides (the other 13 compounds). In the analyzed samples of E. longistipitata, 14 fatty acid–related compounds were identified, but coumarins and furochromones that were found in E. longistipitata were the most interesting result; furochromones khelloside, khellin, visnagin, and cimifugin were found in E. longistipitata for the first time. Coumarins 5,7-dihydroxy-4-methylcoumarin, scoparone, fraxetin, and luvangetin and furochromones methoxsalen, 5-O-methylvisammioside, and visamminol-3′-O-glucoside were detected for the first time in the genus Eranthis Salisb. For all the above compounds, the structural formulas are given. Furthermore, detailed information (with structural formulas) is provided on the diversity of chromones and furochromones in other representatives of Eranthis. The presence of chromones in plants of the genus Eranthis confirms its closeness to the genus Actaea L. because chromones are synthesized by normal physiological processes only in these members of the Ranunculaceae family.